Manipulator tong attachment for lift trucks



March 12, 1957 J. H. NELSON MANIPULATOR TONG ATTACHMENT FOR LIFT TRUCKS Filed D80. 10, 1954 4 Sheets-Sheet l (John H. Nelson March 12, '1957 J. H. NELSON MANIPULATOR TONG ATTACHMENT FOR LIFT TRUCKS 4 Sheets-Sheet 2 Filed Dec. 10, 1954 iii *EIZTUT d ofin H. [Va/5011 %ZLZZ775 March 12, 1957 J. H. NELSON 2,784,861

MANIPULATOR TONG ATTACHMENT FOR LIFT TRUCKS Filed Dec. 10, 1954 4 Shets-Sheet 3 42b 4% 45b 47% 4 44b 40 L 0 I SI 12k. r 455 y 25 25b a" 510: M 22- L i 49 Q 1 7 41:

71 r31 [L Q 54 55 59 E1772 7711s T (fa/UT H. Nelson March 12, 1957 J. H. NELSON 2,784,861

MANIPULATOR TONG ATTACHMENT FOR LIFT TRUCKS Filed Dec. 1 o, 1954 4 Sheets-Sheet 4 EYE 17.1fm T John H. [Vs/.5012

United States Patent MANIPULATOR TONG ATTACHMENT FOR LIFT TRUCKS John H. Nelson, Palos Park, Ill., assignor to Krupp Forge Company, Chicago, Ill.

Application December 10, 1954, Serial No. 474,534

4 Claims. (Cl. 214-653) This invention relates to a mechanical manipulator or device for the handling of articles, more particularly, to improved manipulator for the handling of heavy or cumbersome articles, which must be transported or moved from one place to another or from one work station to another in a plant wherein work is to be done on such articles at various work stations.

Although the instant device may be used in a number of applications, as will be apparent to those skilled in the art, the instant device has been found to be particularly useful in the metal working arts, wherein the work piece is transported, for example, from a furnace to a forge or similar metal working station. As will be appreciated, in the usual metal working plant it is necessary to maintain a reasonable amount of working space between the various furnaces and the various metal working stations, whereat forging, punching, etc., may be carried out. Also, actual manipulation of work pieces which are being treated at a forging station, for example, is necessary. In other words, the work piece must be rolled over after so many blows by the hammer or otherwise moved during a forging operation.

As will be appreciated, in the large size metal working shops the work pieces are of substantial size and weight and the problem of transporting such pieces from one station to another is greatly complicated by the cumbersome heavy character of such pieces. Also, the entire operation is further complicated by the necessity for moving or rotating such pieces during a given forging operation. Heretofore, permanent tracks have been installed at great expense so that carriages movable thereon may be equipped with clamps, hoists and the like for carrying out the necessary manipulation of the articles. Also, overhead hoists or similar lifting devices mounted on overhead tracks have been used. Because of the weight of the articles involved, the structures heretofore used have been more or less permanent in character thus limiting greatly the flexibility of the overall operation in moving pieces from one work station to another. Also, the ordinary track-mounted hoist device is not adapted to carry out a great number of the movements required in manipulating. certain pieces, particularly during complicated forging operations, and because of this it is necessary to employ manual aid in the form of a number of employees using levers and similar relatively crude devices. Also, the work by these employees involved numerous safety hazzards, since they must be near the work piece at such work station locations as the presses and the forges.

In solving these various problems, this invention provides an entirely new concept in the use of the basic structure of an industrial lift truck equipped with a plurality of unique handling devices adapted to securely grasp the articles to be handled and also to move such articles in the plurality of different manners required for manipulation thereof in a forge shop or similar industrial plant.

The instant device affords the flexibility of movement 2,784,861 Patented Mar. 12', i957 from one place to another that is provided by the lift truck itself. The instant device further comprises means for manipulating the article carried thereby to raise and lower the same, swing or tilt the same through a limited are in a vertical direction, swing the same through an unlimited arc in the generally horizontal direction (by movement of the truck body), and rotate the article about a given axis. In addition, the instant device comprises unique arms equipped with hands presenting opposed allochiral palms which grasp and securely retain the article for the manipulation required.

It is, therefore, an important object of the instant invention to provide an improved manipulator for the handling and transportation of heavy or bulky articles.

It is another object of the instant invention to provide an industrial lift truck including a telescopic hoist assembly, a supporting frame carried by the hoist assembly and selectively raised and lowered therewith, a turn table rotatably mounted on said frame, first drive means selectively rotating the turntable, a pair of arms corotatably carried at their base ends by said turntable and extending outwardly therefrom, a pair of hands carried at the outer extremeties of said arms and presenting opposed allochiral palms for grasping articles to be handled by the truck, and second drive means selectively swinging the arms and hands away from and toward each other to effect selectively releasing and grasping of articles by said palms.

It is a further object of the instant invention to provide an improved industrial lift truck assembly comprising rotatably mounted arms having hands at the outer extremities thereof which, in closed position, define sub stantially a polygonal shaped space for grasping heavy articles during the manipulation and transportation thereof.

Other objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed disclosure thereof and the drawings attached hereto and made a part hereof.

On the drawings:

Figure l is a view in elevation of an industrial lift truck having rotatably mounted arms in accordance with the instant invention;

Figure 2 is an enlarged elevational view of the arms and rotatable carriage assembly therefor shown in Figure 1;

Figure 3 is a top plan view of the carriage assembly and arms shown in Figure 2, showing in dotted lines the open position of the arms and in solid lines the closed position of the arms;

Figure 4 is an enlarged sectional elevational detailed view with parts shown in section, with parts broken away, taken substantially along the broken line indicated in Figure 3 as IV--IV;

Figure 5 is an end elevational view of the rotary carriage assembly, taken generally along the broken line V-V of Figure 2 and showing certain parts to the rotary mechanism not shown in Figure 2;

Figure 6 is a view comparable to Figure 5, but showing a different embodiment of the invention;

Figure 7 is a top plan view of the rotary carriage shown in Figure 6; and

Figure 8 is a side elevational view of the rotary carriage ofFigures 6 and 7, with parts broken away and parts shown diagrammatically.

As shown in the drawings:

In Figure 1, a motor propelled industrial lift truck, indicated generally by the reference numeral it is shown having front drive wheels 11 driven by suitable connections (not shown) from either an internal combustion motor or an electric motor (not shown) within the hood 13 suitably positioned at the rear of the truck 10 for- 3 weight balance on the truck 10. The truck also has rear steering wheels 12 operatively connected to a manually operated steering wheel 14 for the operator of the truck 10. A control panel 15 mounted near the operators steering wheel 14 provides a conventional snap action mechanical contact to controller for the conventional four speeds forward and reverse.

A telescopic hoist frame 16 is mounted on the front end of the truck 10, swingable about pivots P on opposite sides of the truck 10 which are connected to side plates 17 suitably secured to the bottom of the hoist assembly 16 (as by welding). A double action piston and cylinder 18 connected by a pivot 19 to the central rear of the hoist assembly 16 and suitably mounted on the truck 10 actuated by a lever, such as the lever 20 on the control panel 15, which in turn actuates a magnetic contactor in a pump motor circuit (not shown) connected to the hydraulic cylinder 18 controls the driving of the hydraulic cylinder or drive means 18 so as to effect tilting of the hoist assembly 316 about the pivots P in a manner well understood by those skilled in the art. This tilting movement of the hoist assembly 16 effects limited arcuate or swinging movement of the hoist assembly 16 and the parts carried thereby (which will be described hereinafter) in a generally vertical plane, so that parts extending generally normal to the vertical plane of the telescopic device 16 may swing from beneath the horizontal to substantially touch the ground support G for the wheels 11 and 12 to a limited number of degrees (i. e. about 20 to above the horizontal.

The telescopic hoist assembly 16 is a conventional structure for industrial lift trucks which comprises cer tain conventional operating parts (here shown generally diagrammatically) as side channel members 16a, a slide member 16b carried between the channel members 16a for guided vertical movement, a looped lifting chain member 165 anchored to the top of the slide 1612 and looped over a pulley 16a and anchored to the side channels 16a at the points 316e, and a hydraulic piston and cylinder 16f anchored to a top frame 16g and operatively connected to the pulley 16d for movement vertically up and down to lift the slide 16!). As will be appreciated, the positioning of the various elements within the hoist assembly 16 is here shown in a simplified form which in actual practice is altered so as to effectively permit movement of the slide 36b the full length of the channel 16. The various telescopic hoist assemblies 16 for raising and lowering a slide member 16/) are well understood by those skilled in the art.

The slide 1657 carries a supporting frame 21 suitably secured thereto with bolts (not shown) which is raised and lowered therewith. The supporting frame is posiiioned on the face of the slide 16/2 and the hoist assembly l6 and is generally rectangular in shape extending the distance between the side channels 16a of the assembly 16, and the frame 21 is tiltable with the assembly Carried by the frame 21 are a turntable 22 rotatably mounted on the frame 21, first drive means 23, in the form of a hydraulic motor, selectively rotating the turntable 22, a pair of arms 24a and 24]; corotatably carried at their base ends 25!: and 25b by a carriage 26 co-rotatably attached to the turntable 22, a pair of hands 27a and 27h are carried at the outer extremities of the arms 2 5a and 2%, respectively, and second drive means 28, in the form of a hydraulic cylinder, in the carriage 26 selectively swing the arms 24a and 24b away from and toward each other to effect selectively releasing and grasping of articles (not shown) by the hands 27a and 271), respectively.

Referring now to Figures 3, 4- and 5, it will be seen that the turntable 22 is a generally circular member suitably mounted on a fixed axle member 22 (Figures 1 and 2) secured to the frame 2i. and rotatably carrymg the turntable 22. The turntable 22 comprises a front generally annular plate 22a and a rear plate 2211 with gear teeth 22c at the outer periphery thereof. The gear teeth 22c are engaged by a pinion gear 3i) (Figure 5) which in turn is operatively engaged by a worm gear 31 that is driven by the hydraulic motor 23 mounted on the frame 21. As those skilled in the art will appreciate, the hydraulic motor 23 is suitably connected to a hydraulic pump circuit (not shown) controlled through the switchboard 15 which selectively drives the hydraulic motor 23 forwardly or in reverse so as to rotate to the worm gear 371 in either direction and in turn to rotate the turntable 22 in either direction through the gear system 30 and 220 so as to effect complete rotation of the turntable 22 through 360 in either direction. The turntable 22 is carried primarily by the axle member 29; but a pair of rollers 32 and 33, rotatably carried by supports 34 and 35, respectively, secured to the frame 21 resist outward tilting of the turntable 22 at the top thereof, with the rollers 32 and 33 rotatably engaging the top outer side of the front face 22a of the turntable 22. Bottom rollers 36 and 37 (also secured to the frame 21 by mounting members 38 and 39, respectively, permitting rotation of the rollers 36 and 37) engage the underside of the bottom of the turntable 22 in a similar manner for the purpose of preventing tilting of the bottom portion of the turntable 22 toward the frame 21.

The arms 24- and 24b are co-rotatably carried on the turntable 22 by means of a carriage 26. The carriage 26 is a generally rectangularly cross-section housing having side Walls 26a and 26b (extending vertically) secured (by welding) to outwardly extending angle irons 4t) welded at their base ends to the turntable 22 and removable top and bottom walls 26c and 26d, respectively, secured (by bolts, not shown) to the irons 40 carrying the side walls 26a and 26b (Figure 5). The turntable 22 is, of course, rotatable in a generally vertical plane about its axis (i. e., the axle member 29) and the carriage 26 extends generally axially outwardly from the turntable 22, being centrally positioned thereon.

Pivot pins, in the form of heavy bolts 41a and 41b are received through suitable apertures in the carriage bottom 26d and extend upwardly through suitable apertures in the carriage top 260 to be secured in position by threaded engagement of nuts 42a and 42b, respectively. The pivots 41a and 41b carry lower spacers 43a and 43b and upper spaces Ma and 4-411, respectively, which fix the relative (horizontal) position of the base end portions 25a and 25b, respectively, of the arms 24a and 24b in the carriage 26. The pivot pins 41a and 41b are suitably received in apertures in the arm base portions 25a and 25b, respectively so as to afford pivotal mounting for the arms 24a and 24b; and the upper and lower spacers 43a, 43b and 44a, 44b retain the arm base portions 25a and 25b, respectively, in position on the pivot pins 410 and 41b, respectively.

As will be seen most clearly from Figure 3, the arm base portions 25a and 25b are pivotally mounted on the pins 41a and 41b, respectively (here shown diagrammatical'ly for the sake of simplicity) near the extreme ends or shoulder portions 45a and 4512, but spaced inwardly (with respect to the arms 24a and 2417) from the actual base end extremities or shoulder portions 45a and 45b of the arm base ends 25a and 25b. The shoulder portions 45a and 45b, respectively, are flared or turned outwardly behind the side walls 26a and 26b and between the angle irons 4t) and are then swept backwardly toward pivot pin mountings 46a and 4612, respectively, at each end. The drive means 21% carried by the shoulders 45a and 4512 has a hydraulic cylinder 28a suitably equipped with actuating fluid pressure lines in an actuating fluid pressure system (not shown) having a movable piston 281) connected to the pivot pin 46:: While the opposite end of the cylinder 28a is pivotally anchored to the pivot 461'), so that actuation of drive means 28 to open the arms 24 and 24b involves drawing of the piston arm 2812 into the cylinder 28a to pull the pivot pins 46a and 46b together, as shown in the light lines in Figure 3.

The arm base end portions 25a and 25b are also equipped with supports (to be described) for maintaining proper alignment therebetween. As shown, pivot pins 47a and 48a are positioned in the arm base portion 2501 on opposite sides of the main pivot 41a and pivot pins 47b and 48b are suitably mounted in the arm base portion 25b on opposite sides of the main pivot 41]) in a similar manner. Linking bars 4b and 50 interconnect the pivot pins, so that the linking bar 50 interconnects the pin 4761 with the pin 48b (a linking bar connecting the tops of these two pins) and the linking bar 49 inter- Connects the pivot pins 47b and 43a. As those skilled in the art will appreciate the linking bars 49 and d cooperate with the floating drive means 28 (which are actual-1y carried by the arm extremities 45a and 45b) so that the arms 24a and 24b will move inwardly and outwardly through substantially the same number of degrees upon driving movement of the hydraulic drive means 28.

The arm base ends 25a and 25b are heavy frame members (preferably of steel or similar high strength material) which extend outwardly from the carriage 26 a short distance and have secured thereto by suitable means (to be described) the arms proper 24a and 24b. As indicated in Figures 4 and 5 particularly, the arm portions 24a and 2425 are rectangular (substantially square) in cross section, and the arms 24a and 24b are suitably seated in opposed V-shaped grooves 51a and 51b formed in the outer ends of the base portions 25a and 25b, respectively, the arms being retained in the grooves 510: and 51b by a series of bolts 52. threadedly engaging the base portions 25a and 25b respectively. For best strength the arms 24a and 24b are turned so as to. present a diamond shaped cross-section received in the V-shaped notches 51a and 51b, whereby the arms 24a and 24b are secured to the base portions 25a and 25b, respectively. As is shown in Figures 3 and 4, however, the diamond shaped cross-section of the arms 2 M and 24b is altered by twisting of the outer extremities of the arms 24a and 24b at 52a and 52b, whereby the initial formation of the hands, indicated generally as 27a and 27b is accomplished. The wrist portions 52a and 52b whereat the arms are twisted so as to form generally square cross-sections are formed in this manner so that the opposed flat sides s thereof may be brought closely together and the hands are then twisted outwardly at 53a and 53b generally normal to the wrist portions 52a and 52b, then through a downward portion 54a and 54b (also generally normal to the plane of the arms 24a and 24b) and then turned to an inwardly extending pair of hand portions 55a and 55b slightly pointed at their inward extremities to facilitate grasping articles. As will be seen in Figure 4, the hand portions 53a, 54a E50, and 53b, 54b and 55b are generally cupped so as to present opposed alloehiral surfaces or palms 56a and 56b, respectively which serve generally to define a polygonally shaped cross-section for the space between the hand members 27a and 27b. As shown in Figures 4, the cross-sectional area of the space between the hands 27a and 27b is approximately a rectangle defined by generally horizontal top and bottom walls (53a, 53b and 55a and 55b) and by generally vertical side walls (54a and 54b). By the use of palm portions 56a and 56b which define generally a polygonal cross-section, it is possible to provide wall portions which may grasp an article so as to provide supporting force components for substantially the entire periphery of the cross-section ofthe article (as here indicated by the cross-section of the space), so that the article will be properly supported during the entire rotary movement of the turntable 22 through 360 about its axis (generally aligned with the axle member 29 and passing through the point a in Figure 4).. The arms 24a and 24b (with integral hands 27a and 27b) swing forward and away from each other in a plane P-P generally passing through the turntable axis (or the point a of Figure 4). The central axis of the polygonal space between the palms 56a and 56b passes generally parallel to but spaced from the turntable axis approximately through a point a in Figure 4. This off set feature of the hands 27a and 27b is found to be advantageous in certain circumstances for rotary manipulation of articles in a forge, for example.

Referring now to Figures 6, 7 and 8, which show somewhat different arm and carriage mountings, it will be noted that a turntable 122 is shown having a structure generally similar to structure of the turntable 22, with a suitable front face portion 122a and a rear gear portion 122]) operatively engaging a pinion gear 130 driven by suitable drive means (not shown), in substantially the same manner in which the drive means 23, pinion gear 30' and turntable 22 cooperate. Also, suitably mounted top rollers 132 and 133 engage the outer face of the turntable 122 and suitably mounted bottom rollers 136 and 137 engage the inner side of the turntable 122. As will be noted, the various elements in Figures 6, 7 and 8 having functions substantially identical to corresponding elements in the previously described figures have reference numerals which are 100 plus the reference numeral assigned in Figures 1 through 5. It will also be noted that an axle member 129 rotatably supporting the turntable 122 is suitably secured to a supporting frame 121 (which is, like the frame 21, suitably secured to the truck hoist mechanism) and actuating fluid for drive mechanism 128 within a carriage indicated generally as 126 carried by the turntable 122 is supplied (with suitable control and actuation means) by means of lines coaxially received within the axle portion 129 and indicated generally at 60in Figure 8.

The carriage 126 is of generally rectangular cross-section and is secured to the central portion of the turntable 122 extending generally axially outwardly therefrom; and the carriage 126 is defined by side walls 126a and 126i) suitably secured to the face of the turntable 122 (as by welding) and top and bottom walls 126s and 126d, respectively, suitably secured to the side walls 126a and 126b (as by bolts). In the embodiment of Figures 6, 7 and 8, the tongs or arms proper 124a and 124b are substantially identical to the arms 24a and 24b with associated hands 27a and 27b and the extended hand portions of the arms 124a and 12 1b are not shown. It will be noted, however, that one of the arms, namely the arm 124a is held against movement While the arm 12% is pivotally mounted, in a manner which will be described hereinafter. In connection with the mounting of the arm 124a, it will be noted that the outwardly extending end of the carriage 126 carries a supporting framework 61 having the general shape of an angle iron and extending outwardly from the front or outer end of the carriage 126 and secured thereto by suitable means (as by welding). The supporting framework 61 has mounted within the V-shaped portion of its angle iron structure a supporting block 62 (Figure 6) which cooperates with the framework 61 to define a V-shaped groove 63 that receives and securely retains one end of the arm 124a by means of bolts 64 in substantially the manner in which the arm 24 is retained in the base portion 25 in the embodiments of Figures 1-5. The arm 124a is thus held against movement.

A protruding framework 65 comparable in shape to the framework 61 also carries a loading block 66 which defines therewith a V-shaped notch 67 receiving and securely mounting the end of the arm 124-]: also by means of bolts 68. The framework 65 is, however, movable and it is carried by a pivot arm 69. The pivot arm 69 has a generally U-shaped bracket 70 wrapped therearound and secured thereto by means of bolts 71 and the legs 70a, 70a of the bracket 70 extend outwardly to embrace a rectangularly cross-sectioned back portion 71 of the framework 65 (which carries the angle iron portion and the loading block 66, as indicated). A suitable pivot pin '72 carried by the U-shaped bracket 70 is received by the framework 65 to pivotally mount to the framework 65. The limited amount of pivotal movement of the framework 65 upon the pivot pin 72 is really sufiicient to afiord best alignment between the arms 124a and 1124b when a load is applied thereto for the purpose of picking up an article. As will be seen, the outer edge of the pivot arm 69 limits pivotal movement of the framework 65 (Figure 7) and as also seen in Figure 7 a guide member 73 carried by the framework 65 presents a cam surface to a mating guide member 74 carried on the framework 126 to further limit pivotal movement of the framework 65 and also to assist in alignment between the framework 65 and the corresponding stationary framework 61. The pivot arm 69 is pivotally mounted on a pivot pin 75 that is carried by the carriage 126, passing through the top and bottom walls 126a and 126d, respectively. The pivot pin 75 carries the pivot arm 65 in the carriage 126 so as to afiord the relative swinging movement between the arms 124a and 1241). Limited sliding movement of the pivot '75 or sliding adjustment of this pivot may be afforded. The end of the pivot arm 6% (Figure 7) opposite the end carrying the framework 65 is connected to a suitable pivot 77 to the drive means indicated generally at 1128. Actually, the drive means 128 comprise a pair of superimposed (as seen in Figure 7) double acting hydraulic piston and cylinder units which are connected to the pivot arm end 69a by a pair of pivots 77, 77. The pivots 77, 77 are connected to the piston rod portions 1281) and'the piston cylinder portions 128a are suitably anchored by means of pivot pins 78 to the side wall 126a of the carriage 126. On the opposite carriage side wall 1126b there is mounted a motion limiting block 79 which extends at one end 79a outwardly beyond the pivot 75 so as to limit outward swinging movement of the pivot arm 69 and which also presents a rear surface 7% which presents inward swinging movement of the pivot arm 69 beyond a certain desired point. As shown in Figure 7 also, a control valve member 79 connected to the fluid pressure inlet means 60 (Figure 8) affords the necessary fluid communication to a plurality of high pressure lines 80 connected at opposite ends of the actuating cylinders 1128a to supply the necessary actuating fluid pressure thereto. The lines 80 are shown only diagrammatically to indicate their general position, since the details of operation of devices of this type are well known to those skilled in the art and need not further be described herein. In the embodiment of Figures 6, 7 and 8, the combination of the fixed arm 124a and a single movable arm 1124b may suffice to provide greater strength than that which may be involved in grasping articles using the embodiment of Figures l-S, since all actuating forces may be applied to a single arm (the arm 1124b) and additional strength may be employed in holding the arm 124a. Also, the grasping of articles of any bulk can usually be handled by the arms 124a and 1241), although the movement of both arms 124a and 1241) does provide for a much wider opening between the hands 27a and 27b, if such is desired. Also, the application of a driving force in a substantially uniform manner by the two arms 24a and 24b, as well as the coordinated movement between these two arms offers a number of advantages in the proper handling of articles.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

. in an industrial lift truck including a telescopic hoist assembly, in combination, a supporting frame carried by the hoist assembly and selectively raised and lowered therewith, a turntable rotatably mounted on said frame, first drive means selectively rotating the turntable, a pair of arms co-rotatably carried at their base ends by said turntable and extending outwardly therefrom, a pair of hands carried at the other extremities of said arms and presenting opposed allochiral palms, said palms being cupped in shape to define a generally polygonally crosssectioned space therebetween in closed position for grasping articles to he handled by the truck, and second drive means selectively swinging the arms and hands away from and toward each other to effect selectively releasing and grasping of articles by said palms.

2. in an industrial truck, in combination, a turntable mounted thereon for rotation about its central axis, a are co-rotatably carried by the turntable, a pair of :ms having base ends extending into said carriage and carried thereby and outer ends extending outwardly axially of the turntable, a pair of hands carried at the outer extremities of said arms and presenting opposed allochiral palms, said palms being cupped in shape to define a generally polygonally cross-sectioned space therebetween in closed position for grasping articles to be handled by the truck, at least one of said arms being pivotally connected to said carriage to accommodate swinging movement thereof toward and away from the other arm, and a hydraulic piston and cylinder assembly in said carriage operatively engaging said one of said arms to drive said arm through said swinging movement.

3. In an industrial truck in combination, a turntable mounted thereon for rotation in a generally vertical plane through 360 about its central axis, a carriage co-rotatably carried by the turntable, a pair of arms having base ends extending into said carriage, pivots in said carriage mounting said arms for swinging movement toward and away from each other in a plane passing generally through the turntable axis, a pair of hands carried at the outer extremities of said arms and presenting opposed allochiral palms for grasping articles to be handled, said palms being cupped in shape to define a generally polygonally cross-sectioned space therebetween in closed position so as to retain articles grasped thereby during full 360 rotation of the turntable, and a hydraulic piston and cylinder assembly carried by and secured to each arm at its base extremity for swinging the arms about said pivots.

4. In an industrial truck, in combination, a turntable mounted thereon for rotation in a generally vertical plane through 360 about its central axis, means raising and lowering said turntable and tilting the turntable, a carriage eo-rotatably carried by the turntable, a pair of arms having base ends extending into said carriage, pivots in said carriage mounting said arms for swinging movement toward and away from each other in a plane passing generally through the turntable axis, a pair of hands carried at the outer extremities of said arms and presenting opposed allochiral palms for grasping articles to be handled, said palms being cupped in shape to define a generally polygonally cross-sectioned space therebetween in closed position so as to retain articles grasped thereby during full 360 rotation of the turntable and raising, lowering and tilting of the turntable, and a hydraulic piston and cylinder assembly carried by and secured to each arm at its base extremity for swinging the arms about said pivots.

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